TiVo HD DVR - No Video Output

I have a TiVo HD DVR TCD658000 which was working fine awhile ago; now, though, it no longer generates video output.

When I power up the unit, the green power light comes on and the hard drive/drive fan starts. However, no video output is generated; the attached TV screen is black. There's no post/startup at all - just a black screen.

Also, when I push the format button on the front of the unit, no format indicating lights light up; finally, when I use the TiVO remote, none of the lights flash on the front screen.

I'd like to know what might be wrong with my TiVO and whether or not it's worthwhile fixing. The TiVO has a lifetime subscription.

In case it matters, I used to have a hard drive expander attached to this unit - currently no hard drive expander is attached. I'm pretty sure that this isn't related but I thought I'd mention it.

One last observation - upon closer inspection, it looks light the green power light is very rapidly flashing - it's not solidly lit. Might this be a power supply issue?

I pulled the cover off my TiVO and looked at the power supply. Visually, all of the capacitors appear to be fine (no bulging/leaking fluids).

Before I spend $100 on a new power supply, is there a good way to test the power supply to verify that it's bad? I have a multi-meter but I've no idea really how to use it to test the power supply.

Thanks in advance for any help.

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First of all, you should use the yellow jack on the back to connect to some sort of video display that offers that same yellow jack input.

That's composite, the lowest common denominator of video connections, and if you're going to see anything, you'll see it on that.

You want to set that meter to DC Volts 0-15, or 0-20, or 0-25, something like that.

Take the black lead, which should be plugged into the - jack, and either alligator clip it to the chassis on the side opposite the power supply, or find a hole on that side you can friction fit it into.

Then the red lead should be plugged into the meter's + jack.

Stand so that the hand that's going to hold the red lead is along a line with the place on the motherboard where the power supply plugs on, and the other side of your body is even further away from the power supply than that, and stick that hand in your pocket when making the measurements.

You can stick the red lead's metal tip down into the individual holes the wires run into in the plug that plugs into the socket on the motherboard until it makes contact with the metal tip crimped onto the end of the wire.

That's called backprobing, cause that's the back of the plug.

The front, of course you can't get to because it's plugged into the motherboard socket.

Since it's what's called a switch-mode power supply it has to have a sufficient load connected to work properly.

The yellow wire is supposed to be +12 Volts, the red wires 5 Volts, and the orange wire, if it uses that, should be 3.3 Volts.

Check those three voltages with the combo data and power plug pulled out of the hard drive and then check them again with the hard drive plugged back in.

I doubt your readings will be exactly 12 or exactly 5 or exactly 3.3, but they should be close, either above or below, and shouldn't change much with or without the hard drive connected to power.

With the hard drive disconnected, the power supply emitted a clicking sound. The voltage reading on the yellow wire fluctuated quite a bit, reading between say 5 and 8 volts or so.

With the hard drive connected, the clicking sound went away and the yellow wire read 11 volts.

Are these readings normal? Is the clicking sound expected? Should I have read 12 volts with the drive connected?

Thanks in advance for your help.

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You should have gotten a lot closer to 12 than to 11.

The clicking sound is probably the supply turning on and off.

Ordinarily it would do so because it didn't have enough of a load (or way too much of a load), but ordinarily the motherboard would be sufficient, at least for a while.

It's not absolutely impossible that something on the power supply circuit board other than bad caps is responsible, but bad caps are at the top, middle, and most of the bottom of the charts.

The power supply board should say either AcBel or 3Y Power Technology. let me know which one and also the model number just in case there's a 3rd model I don't know about, and then I can make you a list of the ones that are group among which the bad one or ones will be.

They probably won't all be bad, yet, but doing them en masse like that will be sure to get the one that is or the ones that are.

Edit to add:

I assume the 5 V and 3.3 V rails measured okay with and without the drive connected?

Is it possible that my hard drive is bad and/or has unreadable data on it and that this is causing the problem?

Since, when I power my TiVO I'm not seeing any video output I assumed that the hard drive is OK - I read somewhere that even with a bad hard drive you'd see startup/post video output - I'm only seeing a black screen with wavy lines.

The reason I'm focusing on the hard drive is that I used to have a drive expander hooked up to this TiVO. I simply removed the drive expander and expected that my TiVO would detect this and offer to reformat the hard drive. Instead - just a black TV screen.

With no drive attached the tivo will show the welcome screen for 5-10 seconds and then a solid grey screen.

You forgot the picture of the caps on the other side of that big heatsink, near where all the wires attach. Those are usually the first to start dying.

I just replaced the capacitors on the same style of power supply. I significantly overrated all of them because I was lazy and thats what Frys had in stock
5x 10v 2200uf replaced with 25v 3300uf
2x 10v 1000uf replaced with 25v 2200uf
1x 16v 1000uf replaced with 25v 2200uf
1x 16v 470uf replaced with 16v 1000uf
These are all the important ones on the DC side of the power supply.

In the post above, I was measuring voltages with the power supply disconnected from the motherboard.

Here are the results with the power supply connected to the motherboard:

No Hard Drive Attached:
Yellow - 12.3V
Red - 4.9V
Orange - 3.34V

Hard Drive Attached:
Yellow - 11.9V
Red - 4.9V
Orange - 3.34V

Do these voltages look OK?

Just for grins, I inserted an M-Card into my TiVO and hooked it back up to my TV. When power was applied I still get the black screen with squiggly lines.

And, I then tried powering up with the hard drive disconnected. Same exact behavior - black screen with squiggly lines.

The only indication that the power supply might be bad is that the green light on the front of the unit is pulsing quite rapidly - from a distance it appears to be solidly lit, only upon close inspection is the pulsing noticeable.

At this point I'm guessing that the motherboard is hosed. Any other thoughts?

With no drive attached the tivo will show the welcome screen for 5-10 seconds and then a solid grey screen.

You forgot the picture of the caps on the other side of that big heatsink, near where all the wires attach. Those are usually the first to start dying.

I just replaced the capacitors on the same style of power supply. I significantly overrated all of them because I was lazy and thats what Frys had in stock
5x 10v 2200uf replaced with 25v 3300uf
2x 10v 1000uf replaced with 25v 2200uf
1x 16v 1000uf replaced with 25v 2200uf
1x 16v 470uf replaced with 16v 1000uf
These are all the important ones on the DC side of the power supply.

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Are you sure upping the capacitance is a good idea? It would seem to change the electrical properties the circuit was designed to operate with.

The upped voltage is fine since that is the tolerance of the capacitor and normally wouldn't affect the circuit.

Are you sure upping the capacitance is a good idea? It would seem to change the electrical properties the circuit was designed to operate with.

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If you follow the traces on the bottom of the power supply you will see that it's an extraordinarily simple design. Many of the capacitors are ran in parallel to each other and there are a couple spots on the board where a capacitor was supposed to go and was never installed.
The only problem I can imagine is that since these are larger there will be less airflow between them.

I attached the TiVO to my TV using the component cable which came with the unit.

Here's what it looks like:

I'm pretty sure my motherboard is fried since the power supply voltages check out and I'm not getting any video output. Does this diagnosis seem right or might it be the power supply/hard drive after all?

Are you sure upping the capacitance is a good idea? It would seem to change the electrical properties the circuit was designed to operate with.

The upped voltage is fine since that is the tolerance of the capacitor and normally wouldn't affect the circuit.

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Changing the capacitance that much is not a good idea because it puts extra load on the power supply--the higher the capacitance the more charge it can hold which means more current being drawn during the charge portion of the cycle, current that has to be supplied by the switching transistors and current that's being diverted from the drive and motherboard.

In other words, it does indeed "...change the electrical properties the circuit was designed to operate with."

Going up a step in voltage rating isn't the end of the world, but when I say step I mean the next industry "standard", not "as much higher as you feel like".

The next step after 10V would be 16, and then 25 after that, then 35, and then 50.

Electrolytic capacitors need to be subjected to voltage below, but near, their rating to keep the electrolyte properly formed.

I wouldn't replace a 10 Volt cap with anything higher than a 25 Volt rated one (at the same uF) except for short time test purposes.